Combined draw-bar and dynamometer



0. M. HATCHER AND E. A. BYE.

COMBINED DRAW BAR AND DYNAMOMETEB.

APPLICATION FILED OCT. 14. 1916. RENEWED MAY 17. 1920.

Patented Dec. 14, 1920.

Inventors? Oscar .jmc/wfw awima e UNlilED STATES PATENT OFFICE.

OSCAR M. HATCHER AND EDWIN A. EYE, OF MANKATO, MINNESOTA, ASS'IGNORS TO"MAYER BROTHERS COMPANY, OF MANKATO, MINNESOTA, A CORPORATION OFIVIINNESOTA.

COMBINED DRAVf-BAP, AND DYNAMOMETER.

Application filed October 14, 1916, Serial No. 125,738.

To all whom 2'!" may concern Be it known that we, OSCAR M. l-Lrrorrnnand EDWIN LL. BYE, citizens of the United States, residing at Mankato,in the county of Blue Earth and State of Minnesota, have invented a newand useful Improvement in Gombined Draw-bars and Dynamometers, of whichthe following is a specification.

This invention has among its objects to combine into a single elementfor use on tractors and other vehicles, a draw bar and dynamometer whichwill simultaneously serve the function of connecting the load to thetractor, of absorbing shocks in draft and of indicating the amount ofload, so that the operator may prevent overloading while the tractor isin operation.

Further objects will be apparent from the following description and tothese ends our invention comprises the features of construction andcombination of parts hereinafter more particularly described andclaimed.

In the accompanying drawing forming part of this specification, Figure 1is a side elevation of a detail of a tractor frame showing our inventionconnected thereto for use; Fig. 2 is a longitudinal section of ourinvention, part of the structure being broken away, and Fig. 3 is a faceView of the indicator.

One exemplification of our invention is illustrated by the accompanyingdrawing, but it will be understood that various modifications arecontemplated within the scope of our claim.

In the drawing, the draw bar proper is constructed with two mainelements A and B, the element A having an eye 2 through which the kingpin 3 is engaged to anchor the draw bar to the yoke member 4: secured onthe frame E of the tractor, whereby the device is free to swinglaterally, and is detachably anchored to the frame The member B of thedraw bar is also formed with an eye or loop 5 for attaching a load to bedrawn by the tractor. Immediately ahead of the eye 5 is a shank 6, whichis guided freely in a longitudinal channel formed by a pair oftransverse angle merobers '7 secured to a depending bracket 8 on theback end of the frame 5. The lowermost of the members 7 supports therearward end of the draw bar, but both bracket members are spaced apartand serve to guide the shank 6 while it moves laterally to accommodatethe load.

The forward end of the shank 6 is bifur- Specification of LettersPatent.

Renewed May 17, 1920. Serial No. 382,081.

cated into two forwardly extending arms 9 and 10. The rearward portionof the member A is formed with a cylindrical head 11 threaded internallyand secured by its threads to a rearwardly ext-ending cylinder 12. Thiscylinder is formed with a pair of longitudinally and oppositely disposedslots 13 in which a connecting pin 14 is guided, said pin being securedthrough th forward ends of the sides 9 and of members B. The slots 13terminate a short distance back of the forward extremity of the cylinder12, said forward end thus acting as a stop to limit the forward movementof the connect ing pin 14 and the member B on member A. 1 pair ofwashers l5 interposed between the sides 9 and 10 and the wall of thecylinder 12 serve as bearing members sliding on the wall of the cylinderand as spacing mem bers to hold the sides 9 and 10 free from thecylinder wall.

Reciprocably disposed in the cylinder is a piston 16, and secured overthe rearward end of the cylinder is a cap 17, which with the pistonforms a pressure chamber in which is placed oil or other liquid 18. Thepiston 16 is formed with a cup 19 in which is placed a helical expansionspring 20, said spring being seated within a circular recess 21 in theinner end of the cup 19 and over a stud 22 formed upon a back stop 28.This back stop has an opening 24: in which the pin 14 is journaled. Thespring acts as a shock absorber, as does also the liquid contained inthe compression chamber formed by the cap and cylinder.

The pressure exerted upon the liquid is registered upon a gage C, inpounds, said gage being connected with the chamber in the cap 17 by apipe 25 or other duct, which may be flexible or rigid according to theconstruction of our invention, which is employed. In use the draw bar asillustrated is free to swing laterally and to a limited extent up anddown. according to the load or pull. One trouble which has heretoforeoccurred in the operation of tractors is overloading. A farmer who isusually unskilled in mechanics will as a rule unknowingly overload themachine because he has had no method of knowing how heavy a load isbeing drawn. This is especially true in plowing, where there is 100%more or less variance in loads at different depths and in differentkinds of soil. This vital objection is entirely overcome by ourinvention, the operator being able to determine at any time by observingthe indicator what amount of load the tractor is pulling. As the loadbecomes greater, the piston correspondingly moves, causing the liquid toassume a greater or less pressure, as will be indicated by the gage,according to the traction power of the tractor. This load is evenlydistributed by the bifurcated draw bar member and the disposition of thehelical spring on the longitudinal axis of the cylinder and its backstop. As the tractor moves ahead over tending obstructions on the roador in the field, the expansion spring 20 and the liquid also minimizethe jar on the tractor and load.

The gage is provided with safety indica tions according to the number ofspeed reductions the power unit carries. In the drawing, the pointer isadapted to indicate by the safety mark 27, the number of pounds at whichit is safe to operate the tractor when running at one speed reductionand by the indication 28, the number of pounds which it is safe for thetractor to pull without overloading at another speed reduction. As manyof these safety indicationsmay be provided on the dial of the gage asthere are speed reductions under which the tractor isadapted to beoperated by the usual internal combustion engine power unit D forexample.

The construction illustrated is extremely simple, inexpensive andaccurate in indicating the amount of load. WVhile the constructionillustrates two draw bar elements movably coupled together with thedynamometer and shock absorber interposed, yet we desire to have itunderstood that these parts may mumuuw be rigidly coupled together orunited when desired and the elements employed reduced in number andmodified in construction within the spirit of our invention.

In accordance with the patent statutes, we have described the principlesof operation of our invention, together with the apparatus which we nowconsider to represent the best embodiment thereof, but we desire to haveit understood that the construction shown is only illustrative, and thatthe invention can be carried out by other means and applied to usesother than those above set forth within the scope of the followingclaim. I

Having described our invention, what we claim as new and desire toprotect by Letters Patent is:

A combined draw bar and dynamometer, comprising, in combination, acylinder, a piston reciprocable in said cylinder, a cap detachablysecured over one end of said cylinder to complete a liquid compressionchamber therein, liquid pressure registering means connected with saidcap, a back stop slidable in said cyllnder, a shock ab sorbing springinterposed between said piston and back stop in said cylinder and a pairof draw bar elements, one being pivotally connected with said back stopto provide up and down swinging motion and the other pivotally supportedto provide lateral swinging motion.

In testimony whereof, we have signed our names to this specification.

OSCAR M. HATCHER. EDWIN A. BYE.

